Multi-Provider Routing ("Cloud Hub")

Status: ✅ Implemented in v0.6.0 Issue: #18Commit: f36d138 — feat(providers): add MultiProvider for multi-cloud routingBranch: feature/cloud-native-v1

Problem

Currently, a single server instance is locked to one provider type (S3 OR Azure OR GCS). Users managing multi-cloud environments need separate server instances for each provider. This is operationally complex and wastes resources.

Design

Goal

A single cloud-fs-mcp instance routes requests to the correct provider based on the URI scheme:

cloud-fs-mcp multi s3://prod-data az://backups gs://ml-models

Architecture

The current design already supports multiple roots (multiple buckets of the same provider). The change is to allow mixed schemes in the root list and instantiate one provider per scheme:

// src/index.ts — multi-provider mode
const providerMap = new Map<string, StorageProvider>();

for (const root of roots) {
  if (!providerMap.has(root.scheme)) {
    providerMap.set(root.scheme, createProvider(root.scheme, args));
  }
}

VFS Impact

The VFS is already scheme-agnostic — it uses toCacheKey(root, key) which includes the scheme. The StorageProvider is passed at construction. For multi-provider, the VFS would need a provider resolver:

// Option A: Provider-per-root VFS wrapper
class MultiProviderVFS {
  private vfsMap = new Map<string, VirtualFS>();
  
  resolveVfs(root: ParsedRoot): VirtualFS {
    return this.vfsMap.get(root.uri) ?? this.vfsMap.get(root.scheme)!;
  }
}

// Option B: Provider resolver function (simpler)
const vfs = new VirtualFS(
  { getProvider: (root) => providerMap.get(root.scheme)! },
  cache,
);

Option B is simpler and requires changing VFS to accept a provider resolver instead of a single provider instance.

CLI Changes

# Current: provider name is required as first arg
cloud-fs-mcp s3 s3://bucket1 s3://bucket2

# New: "multi" keyword enables multi-provider mode
cloud-fs-mcp multi s3://bucket1 az://container1 gs://bucket2

# Provider-specific options use scheme prefix
cloud-fs-mcp multi s3://bucket1 az://container1 \
  --s3-region us-west-2 \
  --s3-endpoint http://minio:9000

Implementation Plan

1. Refactor VirtualFS constructor to accept a provider resolver function
2. Add multi provider mode to CLI parser
3. Instantiate providers per-scheme from root URIs
4. Per-scheme CLI options (e.g., --s3-region, --s3-endpoint)
5. Ensure all tools resolve the correct provider via root scheme
6. Unit tests: multi-provider VFS routing
7. E2E test: S3 + Memory providers in single instance

Acceptance Criteria

• [x] cloud-fs-mcp multi s3://... az://... starts successfully
• [x] Tools route to correct provider based on path URI scheme
• [x] VFS cache operates correctly across providers
• [x] Existing single-provider mode is unaffected
• [x] Unit tests verify multi-provider routing
• [x] E2E test with two providers in one instance